What is Ionic Contamination Testing and how will it benefit me?
Ionic contamination testing is required as ionic residues remaining from both the PCB manufacturing process and the soldering process may affect the reliability of a finished assembly. In a humid environment, ionic contaminants can cause problems such as shorting between conductors by electrolytic dendrite growth, corrosion that erodes the conductors themselves or loss of insulation resistance. It is therefore important to monitor the level of ionic contamination, giving an indication of the cleanliness and thereby the expected reliability of an assembly.
Ionic contamination is measured by immersing a sample in a test solution of 2-propanol and de-ionised water to dissolve the contaminants. The dissolved ionic substances cause a change in conductivity of the test solution; this change is precisely measured and converted into a contamination value expressed as μg/cm2 NaCl equivalence.